St. Thomas’ Church was built as a chapel of Ease to the Parish Church of Taney, and was dedicated on 3rd December 1874. The church cost £750, which sum was raised in full by the parishioners.

Originally only an Evening service was held each Sunday but in response to local demand Morning Services commenced in 1897. In that year also a Vestry was added at the rear of the Church, and this now forms the organ chamber.

The porch at the front entrance of the Church from Foster Avenue was added in 1904 in memory of the late Henry Barton. The Monk Gibbon parochial hall, which incorporates a residential apartment, was built in 1941, and the Rectory in 1952. Mount Merrion was created an independent parish in 1956.

In 1964 it was found necessary to enlarge the church and it was extended and a Baptistery added, being dedicated on St. Thomas’ Day in 1965. The pews and the seating in the Baptistery area can accommodate a congregation of approximately 160. An unique arrangement of pull-out extensions at the end of some of the pews provides 24 additional seats if required.

The church contains 16 beautiful stained glass windows including one by Evie Hone, one by Alan Tomlin and one believed to be by a Flemish artist.

Canon Trevor S. Hipwell was the first and only Rector of the Parish from its initiation in 1956 until his retirement in 1994. From that time forward the Parish was grouped with the Booterstown parish of St. Philip & St. James and the Rev. Stephen Forde became Rector from 1995 to 1999. The Rev. Arthur Barrett was Rector from 2000 to June 2004. The present Rector is Rev. Gillian V. Wharton who was Instituted in October 2004.

War Memorial

The War Memorial is situated on the South Wall of the Church towards the front. It comprises a large brass plaque on which are inscribed the names and ranks of eighteen members of the Parish who served in the armed forces during the 1914- 1918 war, three of who made the ultimate sacrifice. On either side are two stained glass windows erected in 1920, one as a memorial to those who died and the other to those who served and returned safely.